• Korean Journal of Microbiology
• /
• v.49 no.3
• /
• pp.228-236
• /
• 2013

Campylobacter jejuni is one of important food-borne pathogens causing human gastroenteritis. We isolated 42 strains of C. jejuni from diarrhea patients and 4 food-poisoning outbreaks in 2010, Gyeonggi-do. In this study, 42 strains were tested for genetic characteristics, the serotype distribution and antimicrobial resistant rate. The presence of hipO (100%), cdtB (100%), and mutated gyrA (95.2%) genes was detected in C. jejuni by polymerase chain reaction (PCR). Detection of mutated gyrA gene correlated with ciprofloxacin resistance. Forty isolates had mutated gyrA gene and were actually resistant to ciprofloxacin. Furthermore, comparing the gyrA DNA sequence data, ciprofloxacin-resistant isolates had a mutation of the DNA sequence from ACA (threonine) to ATA (isoleucine). But 41 strains (97.6%) of patient isolates were susceptible to erythromycin and azithromycin. A total of 35.7% among 42 C. jejuni isolates were identified into 4 different serotypes. The serotype distribution of C. jejuni strains were shown to be HS2(B), HS3(C), HS4(D), HS19(O). To investigate the genotypes of C. jejuni isolated in Gyeonggi province, repetitive sequence polymerase chain reaction (rep-PCR) analysis and SmaI-digested pulsed-filed gel electrophoresis (PFGE) profile analysis were performed. From the PFGE analysis of 42 C. jejuni strains, 12 clusters of PFGE profile were obtained. On the other hand, 11 clusters of rep-PCR profile were obtained from 42 strains of C. jejuni.

• Journal of Korean Society of Environmental Engineers
• /
• v.28 no.4
• /
• pp.355-361
• /
• 2006

In this study, effects of influent C/N(COD/Nitrate) ratio and dissolved oxygen(DO) concentration on biological nitrate removal from groundwater were investigated in the fixed-type biofilter. Influent nitrate of 30 mg/L was removed completely by biological denitrification at the C/N ratio of 10 and 4.0, while residual nitrate of 5 mg/L occurred at the C/N ratio of 2.0, which resulted from deficiency of organic electron donor. Furthermore, nitrite was accumulated up to about 5 mg/L as the C/N ratio decreased to 2.0. Increase in DO concentration also inhibited denitrification activity at the relatively high C/N ratio of 5.0, which decreased the nitrate removal efficiency. Although the influent DO concentration was reduced as low as 0.3 mg/L using sodium sulfite($Na_2SO_3$), effluent nitrite was up to 3.6 mg/L. On the other hand, nitrate was completely removed without detection of nitrite at the DO concentration of 0.3 mg/L using nitrogen gas($N_2$) sparging. The organic matter for denitrification in biofilter were in the range from 3.0 to $3.5gSCOD/g{NO_3}^--N$, while utilized these values increased at the high DO concentration of 5.5 mg/L. In addition to the high DO concentration and the low influent C/N ratio, DO control by chemical such as sodium sulfite affected on biological denitrification, which resulted in the reduction of nitrate removal efficiency and nitrite build-up in a biofilter.

• The Journal of the Korean bone and joint tumor society
• /
• v.7 no.1
• /
• pp.13-19
• /
• 2001

Background : The incidence of malignant melanoma is currently increasing at a rate greater than any other cancer occuring in human. At this time, early diagnosis and surgical excision were the mainstay of treatment for patients with malignant melanoma. We reviewed the results of average 4 years of follow-up after surgical excision of total 16 cases of malignant melanoma since 1985. Materials and Methods : There were 16 patients (mean age 58.5 years, 5 men, 11 women). The site of the primary lesion was foot and toe (6), back (3), hand (2), thigh (2), shoulder (1), lower abdomen (1) and lip (1). The lymph node was involved at 9 patients. The histologic diagnosis was made with H-E, S-100 stain, and HMB-45 stain as a special stain. Results : Histologically, there were Clark's stage I for 3 patients, II in 4, III in 2, IV in 3, and stage V in 4 patients. The wide excision only greater than 2cm margin was performed for 4 patients. The wide excision and lymph node dissection were performed for 4 patients. The amputation was only performed for 3 patients, and the amputation and lymph node dissection were performed for 5 patients. After surgical excision, chemotherapy was done with Taxol for each 2 patients of stage IV and V. After long term follow-up for mean 4 years, 4 patients died related with melanoma, 1 patient was recurred, and 11 patients were cured. Conclusion : The incidence of malignant melanoma was rare in Korea, but early involvement of lymph node at initial diagnosis was found in many cases (9/16, 56%). And then, early detection and appropriated excision as well as careful dissection of adjacent lymph nodes will offer the patient the best chance for cure.

• Nuclear Medicine and Molecular Imaging
• /
• v.43 no.1
• /
• pp.55-59
• /
• 2009

Purpose: Lymphoscintigraphy and sentinel node biopsy are used in detection of axillary lymph node metastasis in breast cancer patients, but standardized technique is not established. We compared the results of the injection the morning of surgery (1 day protocol) with the subareolar injection the day before surgery (2 day protocol) with the subareolar injection in patients with breast cancer having lymphoscintigraphy and sentinel node biopsy. Materials and Methods: This study included 349 patients who underwent the breast cancer operation during 2001-2004. One hundred seventy one patients (1 day protocol, 1 hour) was injected 0.8ml of Tc-99m Tin-Colloid (37 MBq) by subareolar injection on the morning of surgery. One hundred seventy eight patients (2 day protocol, 16 hour) was injected 0.8 ml of T c-99m Tin-Colloid (185 MBq) on the afternoon before surgery. Lymphoscintigraphy was performed in sitting position and sentinel node localization was performed by hand-held gamma probe during operation. Result: In the 1 day protocol, 153 cases (89.5%) of the sentinel node were localized by lymphoscintigraphy and 150 cases (87.7%) were localized by gamma probe. In the 2 day protocol, 159 cases (89.3%) were localized by lymphoscintigraphy and 154 cases (86.5%) were localized by gamma probe. There was no significant difference in localization of sentinel node between the 1 day and the 2 day protocol by lymphoscintigraphy and gamma probe (p>0.05, p>0.05). Conclusion: There was no difference the result of localization of sentinel node with subareolar injection between the 1 day and the 2 day protocol in breast cancer patients. Because the 2 day protocol allows the enough time of performing lymphoscintigraphy, it is more useful in localization of sentinel node in breast cancer patients.

• The Korean Journal of Food And Nutrition
• /
• v.29 no.4
• /
• pp.474-479
• /
• 2016

This study aimed to investigate the concentration of vitamin C in Momordica charantia (MC) by cultivar, harvest time, and maturity. The methods for determining vitamin C levels were validated by measuring their linearity, specificity, limit of detection (LOD), limit of quantification (LOQ), precision, and accuracy using HPLC. Results showed high linearity in the calibration curve, with a coefficient of correlation ($R^2$) of 0.9994. The LOD and LOQ values for vitamin C were 0.05 and $0.16{\mu}g/mL$, respectively. The relative standard deviations (RSDs) for intra- and inter-day precision of vitamin C measurements were 2.34 and 1.34%, respectively. Depending on cultivar, the concentration of vitamin C in MC varied from 20.75~107.31 mg/100 g, fresh weight, with an average level $68.85{\pm}25.57mg/100g$, FW. When MC was analyzed by harvest time, the 20150612 MC showed the highest amount of vitamin C ($113.20{\pm}1.89mg/100g$, FW). On the other hand, the highest vitamin C content by maturity was $48.59{\pm}0.87mg/100g$, FW (15 day old MC). This information on the comparative vitamin C levels of MC might be useful to food scientists and should be explored for functional food development.

• Journal of agricultural medicine and community health
• /
• v.9 no.1
• /
• pp.56-66
• /
• 1984

Giardia lamblia is a pathogenic flagellate causing intestinal disorders such as diarrhea, abdominal pain and malabsorption of nutrients. Giardia is mainly infected by the ingestion of contaminated foods per os. Craun (1979) has recently reported that mass infection of this flagellate through the contaminated water supply systems is one of public health hazards. Also, so-called traveller's diarrhea is sometimes caused by Giardia infection (CDC, U.S.A., 1971). However, a few epidemiological studies figuring out the mode of infection or control measures of Giardia infection has been done so far in Korea. The present study was aimed to know the prevalence of Giardia infection in several Korean populations, detectability of this flagellate in water systems and the viability of the cysts against sewages and disinfectants applying to drinking water. In the present study, 388 stool specimens from orphanage children in Chun-joo, Chung-joo, On-yang and Chun-an areas and 538 stool specimens from inhabitants in Woo-do, In-chon, and Chun-joo were examined by formalin-ether concentration technique to detect out Giardia cysts. On the other hand, water samples from 14 sites of Han River and its tributaries were collected in May through July, 1984. Fifty liter of water sample in each sampling site was then filtered through water filtering system deviced by U.S. Environmental Proutection Agency and the sediments rinsed out from the thread rolls, a part of water filtering system, were examined to detect out the Giardia cysts. In order to observe the viability of Giardia cysts in the sewage samples, the cysts were treated in it at $4^{\circ}C$ or $25^{\circ}C$ for 7 through 28 days. For this purpose, the cysts were also exposed to various concentrations of disinfectants such as chlorine, iodine and ozone gas for proper time intervals. After treatment, the viability test of the Giardia cysts were carried out by method of Rice and Schaefer (1981) with minor modification. The results obtained in this study were as follows : 1) The detection rates of G lamblia cysts in the stool specimens were 18.3% in orphans and 4.3% in general examinees. 2) The prevalences of Giardia Infection were higher in the young age groups than in-adults. The highest positive rate was 18.4% in the age group less than 10. 3) Of 14 water specimens sampled from Han River system and its tributaries around the Seoul area, the Giardia cysts were detected from 4 samples, and no cyst was found in the water supply systems. 4) The cysts treated in the sewage survived for 28 days at $4^{\circ}C$ and for 13 days at $25^{\circ}C$. 5) The cysts were completely destroyed within 60 minutes by exposure to 8 mg/l of residual chlorine at 4g and within 30 minutes by exposure to the same concentration of chlorine at $25^{\circ}C$. 6) The cysts were all dead when exposed to 1 mg/1 of iodine for 60 minutes at $4^{\circ}C$ or $25^{\circ}C$. 7) The cysts were destroyed after 10 minute exposure in 0.15 mg to 0.25mg of residual ozone gas per liter. Summarizing the above results, it is considered that Giardia infection is regarded as water-borne disease and the cysts are able to be controlled by the application with the disinfectants in the water supply systems.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.46 no.9
• /
• pp.1097-1105
• /
• 2017

This study examined how much chicken meat was in sausage made with pork. Both real-time polymerase chain reaction (PCR) and internal standard addition were used. Fifty ng of chicken DNA was added to the sausages as an internal standard. The addition of standard DNA increased the amplification efficiency of PCR and confirmed the possibility of quantitative analysis. A QIAamp DNA Micro Kit was used to improve the DNA recovery and amplification efficiency. The density of template DNA and primer were suitable for $3.0{\sim}5.0{\mu}L$ and $0.5{\mu}L$, respectively. Each DNA of pig and chicken was diluted in 10-fold from steps 50 ng to 0.05 ng. The detection limit of both pig and chicken meat was more than 0.05 ng and the correlation coefficient of the standard curve was at least 0.98. The result of the quantitative analysis after heat treatment of 3 samples of pigs and chickens mixed at 70:30 showed a 5.7% difference (64.3:35.7) between the expected value and measured value. The quantitative value was changed by affecting the DNA according to the heat treatment ($70^{\circ}C$, 10 min). An analysis of the pork and chicken content in sausages showed that it was difficult to detect chicken meat and the quantitative value of DNA according to the Ct value was very low. On the other hand, when adding standard material (50 ng of chicken DNA) to the sausages, the Ct value decreased gradually with increasing chicken mixing ratio. Thus, the mixing ratio of chicken in sausages could be estimated.

• The Korean Journal of Pesticide Science
• /
• v.16 no.2
• /
• pp.121-130
• /
• 2012

In analyzing pesticide residue, LLE (liquid liquid extraction) is generally applied as one of the existing methods, but needed quite a lot of organic solvents and analytical apparatuses for the sample pre-treatment. In addition to its long analysis time and complex analytical processes, it is required to develop a more rapid and efficient method at present. In order to establish an economic and simple pesticide residue analytical method, this study carried out a comparative experiment on the existing analytical method with a new sample pre-treatment method named QuEChERS (quick, easy, cheap, effective, rugged and safe), which extracts and refines pesticide components by directly adding solid powder into the sample. Both the two analytical methods showed favorable values of correlation coefficient ($R^2$ > 0.99) of calibration curves. In terms of the detection limit (identification limit), imidacloprid showed 0.02 mg/kg, while the rest of pesticides showed a level around 0.05 mg/kg. The results of this experiment revealed that the recovery of LLE was 92.8-100.9% and the RSD was below 2.5%. On the other hand, the recovery of QuEChERS was 92.2-101.6% and RSD was below 1.9%. As a result of comparing the amount of pesticide residue by the time between the two analytical methods by using Paired t-Test, there was no significant difference between the two analytical methods as the p-value ranged from 0.3148-0.9890. Considering the results of the two methods, the QuEChERS method had similar recovery, compared to the analytical method using the existing LLE, and the analytical time was shortened by about one fourth of that of the existing method. Moreover, since it excludes the use of harmful organic solvents like dichloromethane during the process of extraction, thus leading to protecting experimenters health and remarkably reducing the amount of disused solvents, it is judged as an echo-friendly and economic analytical method.

• Korean Journal of Veterinary Research
• /
• v.44 no.2
• /
• pp.241-249
• /
• 2004

As a part of epidemiologic investigation of tsutsugamushi disease, the wild rodents which were captured in Gyeongnam area were diagnosed with indirect immunofluorescent antibody assay (IFA) and Polymerase Chain Reaction (PCR) to find if they have an antibody against Orientia tsutsugamushi. The conclusion was drawn as followings. (1) The captured 58 wild rodents showed that the subspecies distribution of Apodemus agrarius was 86.2%, Microtus fortis was 8.6% and Crocidura lasiura was 5.2%. (2) The antibody positive rate of O. tsutsugamushi Gilliam, Karp, Karto and Boryong by IFA method was 32.0% in Apodemus agrarius among 50 wild rodents and 40.0% in Microtus fortis among 5 wild rodents, respectively. It was negative in the case of all the 3 Crocidura lasiura. (3) The antibody titers on Apodemus agrarius, Microtus fortis and Crocidura lasiura against Gilliam, Karp, Karto and Boryong were measured between 1:20 and 1:640. The antibody titer against each antigen was in the order Boryong>Gilliam>Karp. (4) O. tsutsugamushi was detected from the blood, spleen and kidney from the artificially infected mice by IFA and PCR. IFA showed the positive response between 3 and 18 days after inoculation. On the other hand, positive response was found from all the samples by PCR. (5) From PCR of the genomic DNA extracted from the blood, spleen and kidney samples of the captured wild rodents, Boryong-specific amplification product with size of 210 bp, which is particular in Boryong, was detected from spleen and kidney samples, but not detected in the blood. (6) Boryong-specific amplification product was detected from spleen and kidney samples which were obtained at 3, 6, 12, 18 and 24 days after the infection with Boryong. But, it wasn't detected from the uninfected samples. (7) From PCR of spleen and kidney samples of the captured wild rodents, it was found that positive rate of O. tsutsugamushi in Apodemus agrarius and Microtus fortis were 25.0% (4/16) and 20.0% (1/5), respectively. From the above results, it can be concluded that Apodemus agrarius resided in Gyeongnam area carried O. tsutsugamushi and PCR method might be a simple, precise, rapid and useful diagnostic tool than IFA for the diagnosis of O. tsutsugamushi.

• Nuclear Medicine and Molecular Imaging
• /
• v.43 no.5
• /
• pp.459-467
• /
• 2009

Purpose: The maximum likelihood-expectation maximization (ML-EM) is the statistical reconstruction algorithm derived from probabilistic model of the emission and detection processes. Although the ML-EM has many advantages in accuracy and utility, the use of the ML-EM is limited due to the computational burden of iterating processing on a CPU (central processing unit). In this study, we developed a parallel computing technique on GPU (graphic processing unit) for ML-EM algorithm. Materials and Methods: Using Geforce 9800 GTX+ graphic card and CUDA (compute unified device architecture) the projection and backprojection in ML-EM algorithm were parallelized by NVIDIA's technology. The time delay on computations for projection, errors between measured and estimated data and backprojection in an iteration were measured. Total time included the latency in data transmission between RAM and GPU memory. Results: The total computation time of the CPU- and GPU-based ML-EM with 32 iterations were 3.83 and 0.26 see, respectively. In this case, the computing speed was improved about 15 times on GPU. When the number of iterations increased into 1024, the CPU- and GPU-based computing took totally 18 min and 8 see, respectively. The improvement was about 135 times and was caused by delay on CPU-based computing after certain iterations. On the other hand, the GPU-based computation provided very small variation on time delay per iteration due to use of shared memory. Conclusion: The GPU-based parallel computation for ML-EM improved significantly the computing speed and stability. The developed GPU-based ML-EM algorithm could be easily modified for some other imaging geometries.